I don't think it is a small thing at all. There is little doubt he has done his ahole moves throughout grr we all have. When you sit and think do you remember more bad than good?
When I first started to detach (or so I thought) I did the same thing. I would think about all the things that would irritate me about my W. This helped me a little because I would get angry and suddenly the pain was not so bad.
I realized that the anger was taking me to a place I did not want to go, so I stopped. Just like that. I realized detaching with anger is not detaching at all, it is creating resentment.
There must have been a lot of good in the M, if not, why are you trying to save it? Why do you hurt so bad?
I only caution you to not detach by remembering the bad, that will not do you any good.
The pain is awful, I know but it will not kill you.
Who was the girl he fell in love with?
Find her!
You have a great opportunity to show changes, a chance I wish I had, so use it and embrace it